1 /* $NetBSD: select_bug.c,v 1.1.1.1 2009/06/23 10:09:00 tron Exp $ */
2
3 /*++
4 /* NAME
5 /* select_bug 1
6 /* SUMMARY
7 /* select test program
8 /* SYNOPSIS
9 /* select_bug
10 /* DESCRIPTION
11 /* select_bug forks child processes that perform select()
12 /* on a shared socket, and sees if a wakeup affects other
13 /* processes selecting on a different socket or stdin.
14 /* DIAGNOSTICS
15 /* Problems are reported to the standard error stream.
16 /* LICENSE
17 /* .ad
18 /* .fi
19 /* The Secure Mailer license must be distributed with this software.
20 /* AUTHOR(S)
21 /* Wietse Venema
22 /* IBM T.J. Watson Research
23 /* P.O. Box 704
24 /* Yorktown Heights, NY 10598, USA
25 /*--*/
26
27 /* System library. */
28
29 #include <sys_defs.h>
30 #include <sys/time.h>
31 #include <sys/socket.h>
32 #include <sys/wait.h>
33 #include <unistd.h>
34 #include <stdlib.h>
35 #include <string.h> /* bzero() prototype for 44BSD */
36
37 /* Utility library. */
38
39 #include <msg.h>
40 #include <vstream.h>
41 #include <msg_vstream.h>
42
fork_and_read_select(const char * what,int delay,int fd)43 static pid_t fork_and_read_select(const char *what, int delay, int fd)
44 {
45 struct timeval tv;
46 pid_t pid;
47 fd_set readfds;
48
49 switch (pid = fork()) {
50 case -1:
51 msg_fatal("fork: %m");
52 case 0:
53 tv.tv_sec = delay;
54 tv.tv_usec = 0;
55 FD_ZERO(&readfds);
56 FD_SET(fd, &readfds);
57 switch (select(fd + 1, &readfds, (fd_set *) 0, &readfds, &tv)) {
58 case -1:
59 msg_fatal("select: %m");
60 case 0:
61 msg_info("%s select timed out", what);
62 exit(0);
63 default:
64 msg_info("%s select wakeup", what);
65 exit(0);
66 }
67 default:
68 return (pid);
69 }
70 }
71
main(int argc,char ** argv)72 int main(int argc, char **argv)
73 {
74 int pair1[2];
75 int pair2[2];
76
77 msg_vstream_init(argv[0], VSTREAM_ERR);
78
79 #define DELAY 1
80
81 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair1) < 0)
82 msg_fatal("socketpair: %m");
83 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pair2) < 0)
84 msg_fatal("socketpair: %m");
85
86 vstream_printf("Doing multiple select on socket1, then write to it...\n");
87 vstream_fflush(VSTREAM_OUT);
88 fork_and_read_select("socket1", DELAY, pair1[0]); /* one */
89 fork_and_read_select("socket1", DELAY, pair1[0]); /* two */
90 fork_and_read_select("socket2", DELAY, pair2[0]);
91 fork_and_read_select("stdin", DELAY, 0);
92 if (write(pair1[1], "", 1) != 1)
93 msg_fatal("write: %m");
94 while (wait((int *) 0) >= 0)
95 /* void */ ;
96 return (0);
97 }
98